The invention discloses a device and method for producing pure neon through neon and helium mixed gas. The device comprises a cooling tank, a helium compressor, a helium expander, a liquid neon dewar, a liquid neon pump and an air bath type vaporizer. A first gas-liquid separator, a second gas-liquid separator, a first nitrogen adsorber, a second nitrogen adsorber, a first plate-fin heat exchanger, a second plate-fin heat exchanger, an electric heater, a third gas-liquid separator, a rectifying tower, the helium expander and a vacuum liquid nitrogen heat exchanger are arranged in the cooling tank. The helium compressor, a helium expander braking end, the liquid neon dewar, the liquid neon pump and the air bath type vaporizer are all arranged outside the cooling tank. The cooling capacity of the device is provided through liquid nitrogen in the vacuum state and the helium expander, ultra-high-pressure gas is prevented from entering the cooling tank, the pressure of the whole process is maintained to be lower than 32 kilograms, heat exchangers are simplified into the efficient plate-fin heat exchangers, mutual switching of liquid nitrogen containers is not needed any more, and therefore a large amount of liquid nitrogen and occupied area are saved, and the whole process is simpler.